How does one safely static_cast between unsigned int and int?

Question

I have an 8-character string representing a hexadecimal number and I need to convert it to an int. This conversion has to preserve the bit pattern for

Answer 1

C++20 will have std::bit_cast that copies bits verbatim:

#include 
#include 
#include 

int main()
{
    int i = -42;
    auto u = std::bit_cast(i);
    // Prints 4294967254 on two's compliment platforms where int is 32 bits
    std::cout << u << "\n";

    auto roundtripped = std::bit_cast(u);
    assert(roundtripped == i);
    std::cout << roundtripped << "\n"; // Prints -42

    return 0;
}

cppreference shows an example of how one can implement their own bit_cast in terms of memcpy (under Notes).

While OpenVMS is not likely to gain C++20 support anytime soon, I hope this answer helps someone arriving at the same question via internet search.